This invention relates to apparatus for sampling the contents of pressurized vessels.
As used herein, the term "pressurized vessels" is intended to cover pressure vessels operable with internal pressures both above and below atmospheric.
While the invention can be applied to pressurized vessels carrying out a number of differing processes, it has particular application to pressurized vessels for cooking food products.
It is a requirement that samples of a product being processed in a pressurized vessel be obtained at points during the process cycle, so as to monitor the processing in order to terminate it at the optimum time.
Known sampling systems require equalizing the interior of a pressurised vessel to that of the ambient atmosphere, opening up the vessel, removing a sample, re-sealing the vessel, and then restoring its internal pressure.
Disadvantages of such systems are:
1. The time necessary to bring the internal pressure of the vessel to atmospheric, and then to restore the vessel to the process conditions, is not consistent with normal production cycles;
2. The sample cannot be truly representative because of the lengthy procedure, and
3. The process would continue to a varying extent while equalization with atmospheric pressure is being achieved, such that it is difficult to pinpoint the actual stage in the process cycle reached when the sample was taken.
With the present invention there is no need to equalize the internal pressure of the vessel with the atmosphere in order to allow a sample to be taken. The sample can therefore be taken without interrupting the process cycle. Furthermore, the time at which the sample is taken can be accurately related to a particular point in the uninterrupted process cycle, and therefore relate more precisely to the state or stage of development reached by the product being processed such that the optimum moment for terminating the processing cycle can be determined.